t0350

const ENCODING_NAME = {
    1:"SQLITE_UTF8",
    2:"SQLITE_UTF16LE",
    3:"SQLITE_UTF16BE"
}

const PAGE_TYPE = {
    2:"INTERIOR_INDEX",
    5:"INTERIOR_TABLE",

t0350

time

• real time and process time
  • real time
    Real time is defined as time measured from some fixed point
  • process time
    Process time is defined as the amount of CPU time used by a process(user/systime)
    time(2), getrusage(2), clock(3)
• hardware clock
  rtc, software clock based on rtc(by counting timer interrupt, once per jiffy)
• software clock, HZ and jiffies

t0350

1. sysctl -a | egrep retires, retries parameter control tcp close linux ip-sysctl
2. when tcp refuses to die

t0350

想记录一下有关划分区间的一个有趣问题，来源是 dijkstra 老爷子的 A discipline of programming。

开始之前我们先来看看快排的区间划分。快排的区间划分就是取分点，分点将左右划分为两个区间。比如分点为 pivot，那么一般的，左区间满足小于等于 pivot，右区间满足大于等于 pivot。

比如，考虑区间 [lo, hi]，我们对它进行划分。

// lo < hi
func partition(A []int, lo, hi int) int {

t0350

1.recast
2.dynamic obstacle
3.obstacle avoidance

t0350

#include <stdio.h>
#include <stdlib.h>
#include <pthread.h>

static int ownership = 1;
static pthread_mutex_t lock;

static void *
odd(void *p) {
  for (;;) {

t0350

scalable events

readings

1. linus' thoughts on epoll
2. scalable events
3. paper

t0350

-- cooperative task scheduler based on lua coroutine
local running_tasklist = {}
local iter_index = 0

local function create_task(f, ...)
    local co = coroutine.create(f)
    table.insert(running_tasklist, {co = co, args = {...}, start = false})
    return co
end

t0350

package main

import (
    "os"
    "fmt"
    "strconv"
)

func sieve(ch chan int, stop chan bool) {
    nextc := make(chan int)

t0350

modulus p = 23, base g = 5
secret a = 6, b = 15
public A = g^a mod p = 8, B = g^b mod p = 19
share secret:
  s = B^a mod p = g^(ab) mod p
    = A^b mod p = g^(ba) mod p = 2